Process for making fluorinated compounds



PROCESS FQR MAKHNG FLUORINATED CQMPGUNDS George Van Dyke Tiers, St.Paul, Minn, assignor to Minnesota Mining and Manufacturing Company, St.Paul, Minn., a corporation of Delaware No Drawing. Filed Sept. 2, 1958,Ser. No. 758,596

19 Ciairns. (Cl. Z6ll553.1)

This invention relates to a novel process for making stable, saturated,polyfiuoro-iodo compounds and to certain of the compounds so produced.This application is a continuation-in-part of my copending applicationSerial No. 579,114, filed April 18, 1956, now abandoned.

Previous methods of making saturated polyfluoro-iodo compounds havecentered about the attachment of perfiuoroalkyl groups to olefinicorganic structures by way of addition reactions of perlluoro iodideswith such olefinic structures. Examples of these methods are illustratedin the articles by Henne et al., J. Am. Chem. Soc. 73, 1791 (1951); byHaszeldine et al., Chem. and Ind, 1951, 684; and by Haszeldine, .l.Chem. Soc., London, 1953, 1199; all of which articles disclose suchaddition reactions with CF 1 to give products, e.g.,

CFgCHRCHICHs wherein the iodide is on a carbon atom separated from theCF group by only one intervening carbon atom. These compounds are thusactivated for dehydrohalogenation under the action of even mild bases,HI splitting out under the action of such bases. Because of this, it isnot feasible to react such compounds with tertiary amines in theproduction of quaternary ammonium iodides and other salts which areuseful surface active agents in organic media as well as emulsionpolymerization agents for fiuorinated monomers.

This invention provides a new and useful process for the production ofstable, polyfiuoro-iodo compounds as addition products of the reactionof a polyfluoroalkyl methyl iodide and an ethylenically unsaturatedaliphatic compound which comprises reacting a polyfluoroalltyl methyliodide represented by the formula Y(CF CH l, wherein Y is hydrogen orfluorine and m is an integer from 1 to about 12, and preferably about 3to 12, with an ethylenically unsaturated aliphatic compoundcopolymerizable with other olefinic compounds under freeradicalinitiation and being represented by the formula wherein the remainingvalences of the ethylenic carbon atoms are satisfied by a combination ofmonovalent radicals, the algebraic sum of the Hammett sigma (para)parameter values of which is not greater than +0.2.

Following the process of the present invention, highly fiuorinated alkyliodides are provided wherein the iodinecarrying carbon atom is separatedfrom the highly fluorinated portion of the molecule by at least twointervening carbon atoms. The resulting compounds are resistant to theloss of H1 under the action of bases and can participate in the widevariety of reactions normally associated with alkyl iodides whilepreserving the advantages of compounds possessing a highly fluorinatedend group, and where the end group is composed of a plurality offluorinated carbons, an inert oleophobic and hydrophobic fluorocarbontail.

Patented Feb. 21, 196i The reaction can be expressed generally asfollows:

Y(0F)mCHtI+n(dH=(:7)-- Y(OF,)moH2(dH+)nI where m and Y are as notedpreviously, and n is an integer having a value from 1 to about 3representing the number of moles of the olefinic compound reacted permole of polytiuoroalkyl methyl iodide. The reaction proceeds by afree-radical mechanism in the presence of a free-radical initiator suchas ultraviolet light, benzoyl peroxide, di-tertiary butyl peroxide,alpha, alpha-azodiisobutyronitrile, and the like.

Olefinic compounds which are not copolymerizable with other olefinsunder free-radical initiation are those which contain, for example,mercapto or 2,5-dihydroxyphenyl groups, substituents such as bromine oriodine bonded to a carbon atom immediately adjacent one of theethylenically unsaturated carbon atoms and similar olefinic compounds.

The concept of the Hammett sigma (para) parameter values is fullyexplained by H. H. Jafi in Chemical Reviews, volume 53 (1953), beginningat page 191, particularly at pages 219-233, wherein are providednumerical values for a large number of substituent radicals. The articlealso provides the basis on which such numerical values may be derived.The article, and informa-v tion contained or referred to therein, isincluded here by reference.

The subject reaction takes placein competition, in many cases, with thetendency of the unsaturated compound to homopolymerize. This may resultin the forma tion of polymers of many monomer units of the olefin beforethe molecule reacts with a molecule of the fluorinated iodide (i.e.,.theratioof fluorinated iodide units to olefin monomer units may be 1:10,1:20 or even higher in a given molecule). The -addition of the olefinicreactant at a rate about equal to its rate of consumption provides forlow concentration of the reacting monomer and favors the production ofthe more desirable lower adducts, i.e., those in which n=13, wherein thebeneficial effects of a fiuorinated group are more pronounced than withhigher adducts. These more desirable lower adducts are best obtainedusing relatively inert olefinic compounds such as octene-l andundecylenic acid which do not homopolymerize. V g

The preferred compounds are those wherein the perfluoroalkyl or omegahydro-perfluoroalltyl group is at least three carbons in length sincethese compounds have stable and inert pe'rfluoroalkyl tails which arecharacteristically oleophobic as well as hydrophobic. While thosecompounds having the three carbon omega-hydroperfluoroalkyl tail are notso stable'or inert as the compounds having completely fiuorinatedtailsflthey nevertheless exhibit marked oleophobic and hydrophobicproperties. Compounds of this invention with either of these tailsimpart unique surface active and surface treatment properties notpossessed by corresponding hydrocarbon compounds, the latter beingoleophilic and often highly soluble in oils and hydrocarbons. Thesecompounds may be coated on a' substrate so as to form a fluorocarbontype surface which is repellant to both water and oils and greases.

For. example, the compound produced by free-radical initiated additionof the 1,1- omega-trihydroperfluorononyliodide (CF H(CF CI-l l to'10-hendecenoic acid, exhibits powerful oleophobic properties. Amonolayer film of this compound deposited on platinum from hexanesolution according to the gen eral procedure of Schulman and Zisman (J.Colloid Sci. 7, 465 (1952)) is repellent to water and to various or- 3ganic liquids, such as glycerol, octyl alcohol, hexachloroa butadiene,tricresyl phosphate, tetradecane, xylene, and bromonaphthalene, asevidenced by their failure to spread when applied to the. surface of.such film. This acid, in the form of a water-soluble salt, is alsohighly effective in lowering the surface tension of water even atextremely low concentrations. 7 I Sincethe co-mpoundswhich may beproduced; by the process herein described may contain a wide variety ofother radicals in addition to the fluorocarbon radical, and the chainlength of the latter may be widely varied, the compounds are found to beuseful in a great number of applications, including surface coatings ortreatments, polymers, waxes, hydraulic fluids, solvents, etc.

The following specific examples will serve to further describe theinvention; however, it is to be understood the specific examples areillustrative only and the invention is not limited thereto. 7

Example 1 Fifteen grams of 1,1-dihydroperfluorobutyl iodide (CgFqCHgI),5.4 grams of l-octene (CH =CHC H and 0.8.gram of ditertiary butylperoxide were sealed in a 30 ml. heavy-walled glass ampoule and theampoule was heated to 150 C. for 16 hours. Upon distillation of thereaction product there was recovered 2.7 grams of unreacted C F CH I and11.3 grams of the 1:1 adduct c r cn crncmo n for a yield of 68% based onthe unrecovered iodide. The boiling point of the adduct was found to be134 C. at a reduced pressure of 20 mm. of mercury and its refractiveindex, 21, was 1.4162. Analysis;

Calculated for Found C12H1a 1 Percent Percent v 0-- 34. 1 34. 1 F, 31. 531. 2 T" 30. 1 30. 2

'I-'h e. C H alkyl group is closely similar to the C H group which has aHammett sigma (para) parameter 1 13.6% F, 13.1% I. Found: 13.1% 10.0% 1.

'It. is believed that some iodine has been lost throughdehydrohalogenation.

Example 3- Telomerization of C F CH I with acrylic acid:

In a 180 ml. autoclave, wasplaced C F CH l (62.0 g.), glacial acrylicacid (7.2 g.) and di-t-butyl peroxide (1.2 g.). After sealing'andheating the autoclave for twenty hours at 140 C. (inside temperature),the autoclave was opened and in addition to' recovered unreacted C F CHI, there was obtained 7.5 g. of. white solid telorner. Analysis:

Calcd. for C FCH (CH CHCO H) I: 2 .74% I. Found: 29% F, 2.8% I.

The high value foundfor n in this and in the previous Example 4 Additionof C F CH I to undecylenic acid:

In a 43 ml. autoclave was placed C F CH I (31.0 g.), undecylenic acid(18.4 g.) and di-t-butyl peroxide (1.0 g.). The autoclave was sealed andheated for sixteen hours at C. (inside temperature). The autoclave wasopened and" the product was transferred to a high vacuum short pathstill. 20.5 g. of unreacted C F CH I was recovered as was 13.4 g. ofundecylenic acid. The desired 1:1 adduct, C F CH CH CH1(CH CO I-I had 111.4396 and boiled at 136 C. at 0.010 mm; 11.4 g. of this material wasobtained, the yield being 68% of theoretical after correction was madefor the unreacted C F CH 1 recovered. The formula was confirmed byanalysis: Calcd. for C H F lO 36.5% C, 26.9% F. 25.7% I. Found: 37.0%vC, 26.8% F, 24.7% I; and the infrared spectrum was consistent with thepostulated structure.

' Example-5 Telomerization of C F CH I to n-allyl acetamide:

In a 43 ml. autoclave was placed C F C1-I 1 (3l.0 g.), n-allyl acetamide(9.9 g.) and di-t-butyl peroxide (0.7 g.). The autoclave was sealed andheated for twenty hours at- 145 C. The viscous brownish-black productwas subjected to short path high vacuum distillation. 4.6 g. of brownproduct, 21 1.4610, B.P. 132 at 0.050 mm., was obtained. The infraredspectrum indicated that little, if any, n-allyl acetamide was present inthis fraction. Its formula was established by analysis.

Calcd. for C F CH (CH CHCH NHCOCH I: 21.9% F, 6.9% N, 20.9% I. Found:223% F, 6.0% N, 18.4% I.

This formula of course only reports the average compositions, it was notestablished that the product is a pure compound.

Example 6 Addition of C F CH I to vinyl methyl dichloro-silane: In a 43ml. autoclave was placed 31.0 g. of C3F7CH2I, '14.1 g. of vinyl methyldichloro silane, 1.1 g. of di-tbutyl peroxide. The autoclave was sealedand heated for sixteen hours at 145 C. The reaction mixture wasfractionally distilled at reduced pressure to avoid decomposition-oflhe, iodine-containing products. There was obtained one fraction(2.25 g.). 3.1 94-95 C. at 10 mm. pressure, having n 1.4392. Thismaterial was identilied as the 1:1 adduct by analysis. 1.

Calcd. forC F CH (CH CHSiCH Cl 1: 15.7% C1, 28.2% .1. Found? 18.6% CI,26.0% I. 7

Theanalysis suggests that a small amount of the 1:2 adduct was presentas impurity. Afhigher boiling fraction, 13.1. 170 C. at 10 mm., n 1.4650(2.0

g.) was identified by analysis as principally the 1:3 ad-- duct.

Calcd..for C F CH (CH CHSiCH Cl I: 29.0% C1, 17.3% I. Found: 30.3% C1,15.1%-I.

l Example 7. V

Equimolar quantities of. H(CF CH I' and octene-l were placed in along(approx. 2 ft.) upright, thin Pyrexl tube shaped like a test tube. Thetube was then irradiated under normal room temperature (about 25 C.)with ultra violet light by placing the tube about two inchesfrom aquartz-mercury-arclamp for several a s The contents of the.tube werethen evaporated to. a constant weight product over a steam bath, whichproduct represented about an 11% yield. i

This. modest a H(CF:)4CH1CH:CHI

separated from residue by dissolution in about 50 ml. perfluorinatedethyl cyclohexane and subsequent decantation followed by evaporation ofsolvent, was an amber colored oil, n 1.4406. Nuclear resonance spectrumanalysis of this oil confirmed the presence of the HCF group byregistering a triplet peak at 4.017. The presence of the CHI group wasconfirmed by the presence of a broad peak at 6.041; characteristic ofthis group in this type of compound. The presence of the CH group andthe CH groups was also established by nuclear resonance spectrum peaksat 9.101- and 8.691- respectively. It is to be noted that the CH CH andCH1 nuclear resonance peaks of this compound are essentially duplicatesof those for the product of Example I.

The absence of unreacted starting materials in the product wasestablished by the absence of the triplet peak at 6.381, which ischaracteristic for H(CF CH I, and further verified by the absence of anypeak at 4.947, which is characteristic for octene-I. The meaning of the1- units is described in my paper Proton Nuclear Resonance Spectroscopy.I. Reliable Shielding Values by Internal Referencing WithTetramethylsilane which can be found in the August 1958 Journal ofPhysical Chemistry, and this information is incorporated herein byreference.

The compound structure was also established by chemical analysis, thecalculated weight ratio of fluorine to iodine being 1.20, the ratiofound being 1.29; C, calc.,' 34.4%; C, found, 39.9% (indicating smallamt. of n=2 adduct).

Example 8 Equimolar quantities, 12.78 g. and 4.62 g. respectively ofC3F7CH2I and octene-l, were mixed together in a 10 ml. open mouth flaskequipped with a long neck. The flask was then placed, at normal roomtemperature, about an inch from a quartz-mercury-arc lamp forapproximately 12 hours. The mixture progressively darkened during thisperiod to a dark amber color.

After removal from the flask at the end of the reaction period a portionof the reaction mixture was air dried on a steam bath to a constantweight residue, which showed a 13% conversion to the desired reactionproduct, C F CH CH CHIC H the product identification being confirmed byboth infrared spectral analysis and nuclear magnetic resonancespectroscopy.

Among other olefinic compounds which provide desirable adducts whenreacted with polyfluoroalkyl methyl iodides in the practice of thisinvention are terminally unsaturated straight chain monoolefins, such asethylene, propylene, butylene, etc.; allyl chloride and higherterminally unsaturated olefinic chlorides; 4-bromobutene-l and higherterminally unsaturated olefinic bromides; vinyl and isopropenyl estersof aliphatic acids, such as vinyl acetate, isopropenyl acetate, etc.;vinyl alkyl ethers as vinyl methyl ether, vinyl isobutyl ether, etc.;vinyl methyl thio ether, vinyl ethyl thio ether, etc.; allyl acetate andhigher allyl esters; methallyl propionamide, etc.; 3-butenoic acid andhigher terminally unsaturated carboxylic acids; olefins of the type CH=CRR where R and R are alkyl; vinylidene fluoride; alicyclics witholefinic substituents; internal olefins, i.e., butene-2-, pentene-2,etc.; internally unsaturated longer chain bromides, and chlorides;cyclic olefins, i.e., cyclopentene, cyclohexene, etc.; olefinic silanessuch as vinyl methyl diethoxy silane, vinyl triethoxy silane, vinyltrichloro silane, 4-cyclohexenyl tricnloro silane and 4-cyclohexenylmethyl dichlorosilane.

The algebraic sum of the Hammett sigma (para) parameter values of thesubstituents bonded to the ethylenic carbon atoms of any given olefiniccompound of the aforementioned series does not exceed +0.2.

Compounds produced by the method described hereinbefore can participatein many reactions associated with normal alkyl iodides. They canbe'hydrolyzed to alcohols with aqueous bases, they can be converted toamines b? by reaction with ammonia, and to nitriles by reaction withKCN, and can participate in many other such reactions.

Those compounds wherein the fluorinated tail" is three or more carbonatoms in length are particularly valuable because this highly inert tailrepels both water and oil while the iodide group provides a ready meansfor attaching the compound to a solubilizing group, or, alternatively toa resin forming or adsorbable group suitable for surface coatingapplications.

What is claimed as new is as follows:

1. A process for the production of stable, polyfluoroiodo compoundscontaining a highly fluorinated end group and an iodine carrying carbonatom separated from said end group by at least two intervening carbonatoms, said process comprising reacting in the presence of an activesource of free radicals a polyfiuoroalkyl methyl iodide corresponding tothe formula Y(CF CH I wherein Y is a member of the group consisting ofhydrogen and fluorine and m is an integer from about 1 to" 12, and anethylenically unsaturated aliphatic compound copolymerizable with otherolefinic compounds under free-radical initiation and corresponding tothe formula the free valences of the ethylenic carbon atoms beingsatisfied by a combination of monovalent radicals, the algebraic sum ofthe Hammett sigma (para) parameter values of which is not greater than+0.2, and usefully recovering as addition products of the reaction,compounds represented by the formula wherein n is an integer from 1 toabout 60.

2. A process for the production of stable, polyfiuoroiodo compoundscontaining a highly fluorinated end group and an iodine carrying carbonatom separated from said end group by at least two intervening carbonatoms, said process comprising reacting in the presence of an activesource of free-radical a polyfluoroalkyl methyl iodide corresponding tothe formula Y(CF CH I wherein Y is a member of the group consisting ofhydrogen and fluorine and m is an integer from about 1 to 12, and anethylenically unsaturated aliphatic compound copolymerizable with otherolefinic compounds under free-radical initiation and corresponding tothe formula the free valences of the ethylenic carbon atoms beingsatisfied by a combination of monovalent radicals, the algebraic sum ofthe Hammett sigma (para) parameter values of which is not greater than+0.2, and usefully recovering as addition products of the reaction,compounds represented by the formula Ywrnmcmuin-i nr wherein n is aninteger from 1 to about 3.

3. A process for the production of stable, polyfluoroiodo compoundscontaining a highly fluorinated tail" and an iodine carrying carbon atomseparated from said tail by at least two intervening carbon atoms, saidprocess comprising reacting in the presence of an active source of freeradicals a polyfluoralkyl methyl iodide corresponding to the formulaY(CF ),,,CH I wherein Y is a member of the group consisting of hydrogenand fluorine and m is an integer from about 3 to 12, and

an, ethylenically unsaturated aliphatic c mp und copolyze'raessn'gerizable, with other ol'efinic compounds under freeradical initiationand corresponding to the formula the free valences of the ethyleniccarbon atoms being satisfied by a combination of monovalent radicals,the algebraic sum of the Hammett sigma (para) parameter values of whichis not greater than +0.2, and usefully recovering as addition productsof the reaction, com

pounds represented by the formula wherein n is an integer from 1 toabout 3. v

4. The process of claim 3 wherein Y is fluorine. 5. The process of claim3 wherein Y is. hydrogen.

6 Polyfluoro-iodo compounds containing a highly iluorinated tail and aniodine carrying carbon atom PPQ I Q, m. Said tail by at least twointervening carbon atoms and corresponding to the formula wherein Y isselected from the group consisting of hydro gen and fluorine, m is aninteger from 3 to 12, n is an integer from 1 to 3, and R is a memberselected from the group consisting of hydrogen, and'alkyl, andsubstituted alkyl radicals containing from 1 to 10 carbon 7.Polyfluoro-iodo compounds containing a highly fiuorinated tail and aniodine carrying carbon atom separatedfrom said tail by at. least twointervening carbon atoms and corresponding to the formula wherein Y isselected from the group consisting of hydrogen and fluorine, m is aninteger from 3 to 12, i2 is an integer from 1 to about 60, and R is amember selected from the group consisting of hydrogen, and alkyl, and

References Cited in the file of this patent UNITED STATES PATENTS2,440,800 Hanford May 4,. 1948 2,715,113 Gordon Aug. 9,.19'55 2,808,425-Hazeldine "oer. 1,1957

QTHER REFERENCES Tarrantz. Development of Fluoro-Sil'icone Elastomers,"Wright Air Development Center, Technical Report 55-200, part 1, (August1955), page 24.

1. A PROCESS FOR THE PRODUCTION OF STABLE, POLYFLUOROIODO COMPOUNDSCONTAINING A HIGHLY FLUORINATED END GROUP AND AN IODINE CARRYING CARBONATOM SEPARATED FROM SAID END GROUP BY AT LEAST TWO INTERVENING CARBONATOMS, SAID PROCESS COMPRISING REACTING IN THE PRESENCE OF AN ACTIVESOURCE OF FREE RADICALS OF POLYFLUOROALKYL METHYL IODIDE CORRESPONDINGTO THE FORMULA Y(CF2)MCH3I WHEREIN Y IS A MEMBER OF THE GROUP CONSISTINGOF HYDROGEN AND FLUORINE AND M IS AN INTEGER FROM ABOUT 1 TO 12, AND ANETHYLENICALLY UNSATURATED ALIPHATIC COMPOUND COPOLYMERIZABLE WITH OTHEROLEFINIC COMPOUNDS UNDER FREE-RADICAL INITIATION AND CORRESPONDING TOTHE FORMULA
 6. POLYFLUORO-IODO COMPOUNDS CONTAINING A HIGHLY FLUORINATED"TAIL" AND AN IODINE CARRYING CARBON ATOM SEPARATED FROM SAID "TAIL" BYAT LEAST TWO INTERVENING CARBON ATOMS AND CORRESPONDING TO THE FORMULA